Method for froth flotation treatment of ores



Patented July 21, 1936 METHOD FOR FnoTn FLOTATION TREATMENT or oaEs Frederic A. Brinker, Denver, Colo.

No Drawing. Application February 29, 1932,

Serial No. 595,954

- 15 Claims.

This invention relates to improvements in th froth flotation treatment of ores.

The object of this invention is to materially im-' U prove the recovery of the minerals in their respective concentrates and also to improve the purity of the concentrates or as is usually stated, improve the grade of each respective concentrate in its own mineral content.

It is now possible' by froth flotation of what 10 are called simple ores to make very high recoveries with high grade concentrates. It has however been impossible, up to the present time, on

highest recovery of one mineral sulfide in the presence of one or more other mineral sulfides.

I have discovered in the differential froth flotation separation of complex sulfide ores cdhta'ining iron sulfide together with copper sulfide, or

lead sulfide, or zinc sulfide, or combinations of the above, a method of preparing the ore so as to permit the use of cyanide compounds and render them effective.

I have discovered that ores containing sulfides oiv iron have initially present and have formed,

during the grinding step, iron compounds in various stages of oxidation and that practically all of the oxidized or partially oxidized iron compounds are distinct cyanicides. The above is also 40 true of ores containing copper sulfides with the additional harmful result of the promoting effect of copper compounds. on mineral sulfides that should be inhibited instead of promoted.

My invention consists in removing the deleterious compounds and cyanicides by filtering or rein its reaction on the soluble contents of'the solution and therefore will have no effect whatsoever on the mineral surfaces. It is important and indispensable where iron and zinc sulfides are to be inhibited by the use of cyanides that the latter reach the mineral and this does not happen when the cyanides are dissipated on the soluble material in the pulp. It must be 'borne in mind that the amount of cyanide used is only a fraction of a pound per ton of ore and that, there- 1 fore, even small amounts of soluble materials that react with the cyanide are detrimental.

A description of the invention is as follows: The ore is ground to the desired mesh to liberate the mineral sulfides from each other and from the gangue. On some ores this would ,be 60 mesh, on others 200 mesh. The fineness of grind quent processing and froth flotation operations.

must be determined for each ore.

The ground are pulp is next subjected to a dewatering process which separates from the solid ore particles the solution in which the ore was ground and which solution contains deleterious soluble constituents such as copper, iron and other salts which are detrimental in the subse- The best method of dewatering this pulp is with filters, however other dewatering processes may be used with good results. The solution is either rejected as waste solution or purified and used over again. In some cases the dewatered residue 30 is washed with freshwater.

The dewatered residue resulting from the r moval of the solubles is repulped with water free froth flotation separation.

moving the soluble compounds from the ore pulp prior to the addition of the cyanide compound to the pulp that is to be treated by the froth fiotation separation process. A cyanicide is a compound that destroys the eifectiveness of the cyanide action on the mineral sulfide surfaces. It is possible, in a sulfide ore to have enough soluble iron sulfates in the ore pulp to react completely with the cyanide added to the 68 pulp so the cyanide will be completely dissipated The chemical substance or substancesused for the processing step are cyanide compounds. The most common of these are sodium and potassium cyanides. On many ores it has been found that a zinc compound used with a cyanide compound (or zinccyanide alone) gives better results. Zinc sulfate is the zinc compound commonly used. Other metallic salts may be used with a cyanide compound that precipitate insoluble ferro cyanides, examples being salts of manganese, tin, nickel, etc. The pulp may be either neutral or acid and this condition .will be referred to in the claims as, nonbasic.

At the termination of the processing step, the ore pulp is prepared by the addition of frothing' reagents and suitable flotation collectors for froth flotation separation into froth concentrate and tailing. At this stage the sulfldes of the different minerals are separated into their respective concentrates and the method used for this is well known in the art.

Having described the invention what is claimed as new is:

1. In the froth flotation separation of ores the steps of, grinding the ore in water, removing the soluble material from the ore pulp, repulping the ore with water, adding to the repulped ore pulp a cyanide compound and one or more metallic salts capable of precipitating insolubleferro cyanide, and subjecting the resulting pulp to the froth flotation separation process.

2. In the froth flotation separation of ores the steps of, grinding the ore in water, removing the soluble material from the ore pulp, repulping the I ore with water, adding to therepulped ore pulp a cyanide compound and a zinc compound capable of precipitating-an insoluble ferro cyanide,

and subjecting the resulting, pulp to the froth flotation process.

3. In the froth flotation separation of ores the steps of, grinding the ore in water, removing the soluble material from the ore pulp, repulping the ore with water, adding to the repulped ore pulp a zinc cyanide capable of precipitating insoluble ferrocyanide and subjecting the resulting pulp to the froth flotation process.

4. In the froth flotation separation of ores the steps of, grinding the ore in water, dewatering the pulp, repulping the are with water, adding to the repulped ore pulp a cyanide compound and one steps of, grinding the ore ,in water, flltering the 'ore pulp, repulping the ore .with water, adding to the repulped ore pulp a cyanide compound and one or moremetallic salts capable of. precipitating insoluble ferro cyanide, and subjecting the resulting pulp to the flotation separation 7. In the froth flotation separation of ores, the

steps of, grinding the ore in water. filtering the ore pulpaand removing substantially all the cyanicides carried in the solution, repulping the ore with water, adding zinc cyanide to the repulped ore pulp. and subjecting the resultins pulp to the flotation separation process.

.a zinc compound and a metallic salt capable of 8. In the froth flotation separation of ores, the steps of, grinding the one in water. removing the soluble material from the ore pulp, adding a cyanide compound and a tin compound to the repulped ore pulp, and subjecting the resulting s pulp to the froth flotation separation process.

9. In the froth flotation separation of ores, the steps of, grinding the ore in water, removing the soluble material from the ore pulp, repulping the ore with water, adding to the repulped ore l0 pulp a cyanide compound, a zinc compound and a metallic salt capable of precipitating insoluble ferro cyanide and subjecting the resulting pulp to the froth flotation separation process.

10. In the froth flotation separation of ores, 15

the steps of, grinding the ore in water, removing the soluble material from the ore pulp, adding a cyanide compound, a zinc compound and a tin 'compound to the repulped ore pulp,- and subjecting the resulting pulp to the frothflotation 20 flotation separation procw. 12. In the froth flotation separation of ores the steps of, grinding theore in water, filtering the ore pulp, repulping the-ore with water. adding a cyanide compound and a tin compound to the repulped ore pulp. and subjecting the resulting pulp to the froth flotation separation p 13. In the froth flotation separationo ores,- the steps of, grinding the ore in water. flltering the ore pulp, repulping the ore with water, adding to the repulped ore pulp a cyanide compound,

precipitating insoluble ferro cyanide. and .subjecting the resulting pulp to the froth flotation separation.

14. In the froth flotation separation -of ores, the stepsof, grinding the ore in: water, filtering 4 the ore pulp, repulping the ore with water, adding a cyanide compound, a zinc compound and a tin compound to the repulped ore pulp, the pulp being nonbasic, and subjecting the resulting pulp to the froth flotation separation procass.

15. In the froth flotation separation of ores, the steps of, grinding the ore in water, fllterirrg'v the ore pulp, repulping the ore with water, adding to the repulped ore pulp zinc, cyanide and a metallic salt capable of precipitating insoluble ferro cyanide, and subjecting the resulting pulpto the froth flotation separation process.

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